Abstract
Specific equipment and procedures developed for geomechanical testing of hydrocarbon caprocks were adopted to conduct truly undrained triaxial tests with Opalinus Clay. The amount of pore pressure development during consolidation, and the resulting effective stress, is managed by equilibrating the samples in vacuum desiccators of different relative humidities (vapor equilibration technique) prior to assembling into the test apparatus. We present test results of five Opalinus Clay samples covering a laboratory mean effective consolidation stress range from 5 MPa to 50 MPa. A drained consolidation test was first conducted to determine the appropriate strain rate for consolidated-undrained (CU) triaxial testing. The Skempton ‘B’ parameter was quantified prior to the deformation tests and found to be stress dependent. A distinct stress dependency of elastic moduli is also observed, but normalized with the undrained shear strength there is only a relatively small variation. Within the explored stress range the different stress paths to peak indicate a transition from over consolidated to rather normally consolidated state. However, failure is in all cases dilatant, i.e. associated with a drop in pore pressure and strain-softening (more so at low effective stress). Caprock shales of similar porosity to the Opalinus share many similarities in overall behavior, but also exhibit some slight differences.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Bossart P, Thury M (eds) (2008) Mont Terri Rock Laboratory – Project, Programme 1996 to 2007 and Results. Reports of the Swiss Geological Survey No. 3 – Swiss Geological Survey, Wabern
Ewy RT, Stankovich RJ, Bovberg CA (2003) Mechanical behavior of some clays and shales from 200 m to 3800 m depth. In: 39th U.S. Rock Mechanics Symposium/12th Panamerican Conference Soil Mech & Geotech Eng. MIT, Cambridge, USA, 22–26 June 2003
Ewy RT, Bovberg CA, Stankovic RJ (2010) Strength anisotropy of mudstones and shales. In: 44th U.S. Rock Mechanics Symposium/5th U.S.-Canada Rock Mechanics Symposium, Salt Lake City, USA, 27–30 June, 2010. paper ARMA 10-114
Favero V, Ferrari A, Laloui L (2016) Consolidated-drained triaxial testing of Opalinus Clay. Nagra Int. Ber
Head KH (1998) Manual of Soil Laboratory Testing, vol 3., Effective Stress TestsWiley, Chichester
Hu DW, Zhang F, Shao JF (2014) Experimental study of poromechanical behavior of saturated claystone under triaxial compression. Acta Geotech 9:207–214
Menaceur H, Delage P, Tang A-M, Conil N (2015) The thermo-mechanical behaviour of the Callovo-Oxfordian claystone. Int J Rock Mech Min Sci 78:290–303
Steiger RP, Leung PK (1991) Consolidated undrained triaxial test procedure for shales. In: Proceeding 32nd U.S. Rock Mechanics Symposium, Balkema, pp 637–646
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer International Publishing AG
About this paper
Cite this paper
Giger, S., Ewy, R., Stankovic, R. (2017). Consolidated-Undrained Triaxial Test Results of Opalinus Clay and Comparison with Caprock Shales. In: Ferrari, A., Laloui, L. (eds) Advances in Laboratory Testing and Modelling of Soils and Shales (ATMSS). ATMSS 2017. Springer Series in Geomechanics and Geoengineering. Springer, Cham. https://doi.org/10.1007/978-3-319-52773-4_38
Download citation
DOI: https://doi.org/10.1007/978-3-319-52773-4_38
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-52772-7
Online ISBN: 978-3-319-52773-4
eBook Packages: EngineeringEngineering (R0)